/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Authors: Adrian Hunter
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* Artem Bityutskiy (Битюцкий Артём)
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*/
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/*
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* This file contains miscelanious TNC-related functions shared betweend
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* different files. This file does not form any logically separate TNC
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* sub-system. The file was created because there is a lot of TNC code and
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* putting it all in one file would make that file too big and unreadable.
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*/
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#include "ubifs.h"
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/**
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* ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal.
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* @c: UBIFS file-system description object
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* @zr: root of the subtree to traverse
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* @znode: previous znode
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*
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* This function implements levelorder TNC traversal. The LNC is ignored.
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* Returns the next element or %NULL if @znode is already the last one.
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*/
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struct ubifs_znode *ubifs_tnc_levelorder_next(const struct ubifs_info *c,
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struct ubifs_znode *zr,
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struct ubifs_znode *znode)
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{
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int level, iip, level_search = 0;
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struct ubifs_znode *zn;
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ubifs_assert(c, zr);
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if (unlikely(!znode))
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return zr;
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if (unlikely(znode == zr)) {
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if (znode->level == 0)
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return NULL;
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return ubifs_tnc_find_child(zr, 0);
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}
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level = znode->level;
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iip = znode->iip;
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while (1) {
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ubifs_assert(c, znode->level <= zr->level);
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/*
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* First walk up until there is a znode with next branch to
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* look at.
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*/
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while (znode->parent != zr && iip >= znode->parent->child_cnt) {
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znode = znode->parent;
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iip = znode->iip;
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}
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if (unlikely(znode->parent == zr &&
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iip >= znode->parent->child_cnt)) {
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/* This level is done, switch to the lower one */
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level -= 1;
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if (level_search || level < 0)
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/*
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* We were already looking for znode at lower
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* level ('level_search'). As we are here
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* again, it just does not exist. Or all levels
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* were finished ('level < 0').
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*/
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return NULL;
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level_search = 1;
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iip = -1;
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znode = ubifs_tnc_find_child(zr, 0);
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ubifs_assert(c, znode);
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}
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/* Switch to the next index */
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zn = ubifs_tnc_find_child(znode->parent, iip + 1);
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if (!zn) {
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/* No more children to look at, we have walk up */
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iip = znode->parent->child_cnt;
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continue;
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}
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/* Walk back down to the level we came from ('level') */
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while (zn->level != level) {
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znode = zn;
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zn = ubifs_tnc_find_child(zn, 0);
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if (!zn) {
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/*
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* This path is not too deep so it does not
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* reach 'level'. Try next path.
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*/
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iip = znode->iip;
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break;
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}
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}
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if (zn) {
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ubifs_assert(c, zn->level >= 0);
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return zn;
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}
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}
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}
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/**
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* ubifs_search_zbranch - search znode branch.
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* @c: UBIFS file-system description object
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* @znode: znode to search in
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* @key: key to search for
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* @n: znode branch slot number is returned here
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*
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* This is a helper function which search branch with key @key in @znode using
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* binary search. The result of the search may be:
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* o exact match, then %1 is returned, and the slot number of the branch is
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* stored in @n;
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* o no exact match, then %0 is returned and the slot number of the left
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* closest branch is returned in @n; the slot if all keys in this znode are
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* greater than @key, then %-1 is returned in @n.
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*/
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int ubifs_search_zbranch(const struct ubifs_info *c,
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const struct ubifs_znode *znode,
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const union ubifs_key *key, int *n)
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{
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int beg = 0, end = znode->child_cnt, uninitialized_var(mid);
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int uninitialized_var(cmp);
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const struct ubifs_zbranch *zbr = &znode->zbranch[0];
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ubifs_assert(c, end > beg);
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while (end > beg) {
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mid = (beg + end) >> 1;
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cmp = keys_cmp(c, key, &zbr[mid].key);
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if (cmp > 0)
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beg = mid + 1;
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else if (cmp < 0)
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end = mid;
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else {
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*n = mid;
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return 1;
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}
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}
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*n = end - 1;
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/* The insert point is after *n */
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ubifs_assert(c, *n >= -1 && *n < znode->child_cnt);
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if (*n == -1)
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ubifs_assert(c, keys_cmp(c, key, &zbr[0].key) < 0);
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else
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ubifs_assert(c, keys_cmp(c, key, &zbr[*n].key) > 0);
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if (*n + 1 < znode->child_cnt)
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ubifs_assert(c, keys_cmp(c, key, &zbr[*n + 1].key) < 0);
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return 0;
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}
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/**
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* ubifs_tnc_postorder_first - find first znode to do postorder tree traversal.
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* @znode: znode to start at (root of the sub-tree to traverse)
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*
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* Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is
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* ignored.
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*/
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struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode)
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{
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if (unlikely(!znode))
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return NULL;
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while (znode->level > 0) {
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struct ubifs_znode *child;
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child = ubifs_tnc_find_child(znode, 0);
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if (!child)
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return znode;
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znode = child;
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}
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return znode;
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}
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/**
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* ubifs_tnc_postorder_next - next TNC tree element in postorder traversal.
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* @c: UBIFS file-system description object
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* @znode: previous znode
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*
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* This function implements postorder TNC traversal. The LNC is ignored.
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* Returns the next element or %NULL if @znode is already the last one.
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*/
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struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c,
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struct ubifs_znode *znode)
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{
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struct ubifs_znode *zn;
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ubifs_assert(c, znode);
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if (unlikely(!znode->parent))
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return NULL;
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/* Switch to the next index in the parent */
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zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1);
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if (!zn)
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/* This is in fact the last child, return parent */
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return znode->parent;
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/* Go to the first znode in this new subtree */
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return ubifs_tnc_postorder_first(zn);
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}
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/**
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* ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree.
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* @c: UBIFS file-system description object
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* @znode: znode defining subtree to destroy
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*
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* This function destroys subtree of the TNC tree. Returns number of clean
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* znodes in the subtree.
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*/
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long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
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struct ubifs_znode *znode)
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{
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struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode);
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long clean_freed = 0;
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int n;
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ubifs_assert(c, zn);
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while (1) {
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for (n = 0; n < zn->child_cnt; n++) {
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if (!zn->zbranch[n].znode)
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continue;
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if (zn->level > 0 &&
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!ubifs_zn_dirty(zn->zbranch[n].znode))
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clean_freed += 1;
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cond_resched();
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kfree(zn->zbranch[n].znode);
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}
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if (zn == znode) {
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if (!ubifs_zn_dirty(zn))
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clean_freed += 1;
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kfree(zn);
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return clean_freed;
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}
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zn = ubifs_tnc_postorder_next(c, zn);
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}
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}
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/**
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* read_znode - read an indexing node from flash and fill znode.
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* @c: UBIFS file-system description object
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* @lnum: LEB of the indexing node to read
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* @offs: node offset
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* @len: node length
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* @znode: znode to read to
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*
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* This function reads an indexing node from the flash media and fills znode
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* with the read data. Returns zero in case of success and a negative error
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* code in case of failure. The read indexing node is validated and if anything
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* is wrong with it, this function prints complaint messages and returns
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* %-EINVAL.
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*/
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static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
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struct ubifs_znode *znode)
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{
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int i, err, type, cmp;
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struct ubifs_idx_node *idx;
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idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
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if (!idx)
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return -ENOMEM;
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err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
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if (err < 0) {
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kfree(idx);
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return err;
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}
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znode->child_cnt = le16_to_cpu(idx->child_cnt);
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znode->level = le16_to_cpu(idx->level);
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dbg_tnc("LEB %d:%d, level %d, %d branch",
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lnum, offs, znode->level, znode->child_cnt);
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if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) {
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ubifs_err(c, "current fanout %d, branch count %d",
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c->fanout, znode->child_cnt);
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ubifs_err(c, "max levels %d, znode level %d",
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UBIFS_MAX_LEVELS, znode->level);
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err = 1;
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goto out_dump;
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}
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for (i = 0; i < znode->child_cnt; i++) {
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const struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
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struct ubifs_zbranch *zbr = &znode->zbranch[i];
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key_read(c, &br->key, &zbr->key);
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zbr->lnum = le32_to_cpu(br->lnum);
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zbr->offs = le32_to_cpu(br->offs);
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zbr->len = le32_to_cpu(br->len);
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zbr->znode = NULL;
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/* Validate branch */
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if (zbr->lnum < c->main_first ||
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zbr->lnum >= c->leb_cnt || zbr->offs < 0 ||
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zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) {
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ubifs_err(c, "bad branch %d", i);
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err = 2;
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goto out_dump;
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}
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switch (key_type(c, &zbr->key)) {
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case UBIFS_INO_KEY:
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case UBIFS_DATA_KEY:
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case UBIFS_DENT_KEY:
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case UBIFS_XENT_KEY:
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break;
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default:
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ubifs_err(c, "bad key type at slot %d: %d",
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i, key_type(c, &zbr->key));
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err = 3;
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goto out_dump;
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}
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if (znode->level)
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continue;
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type = key_type(c, &zbr->key);
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if (c->ranges[type].max_len == 0) {
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if (zbr->len != c->ranges[type].len) {
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ubifs_err(c, "bad target node (type %d) length (%d)",
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type, zbr->len);
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ubifs_err(c, "have to be %d", c->ranges[type].len);
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err = 4;
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goto out_dump;
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}
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} else if (zbr->len < c->ranges[type].min_len ||
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zbr->len > c->ranges[type].max_len) {
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ubifs_err(c, "bad target node (type %d) length (%d)",
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type, zbr->len);
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ubifs_err(c, "have to be in range of %d-%d",
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c->ranges[type].min_len,
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c->ranges[type].max_len);
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err = 5;
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goto out_dump;
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}
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}
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/*
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* Ensure that the next key is greater or equivalent to the
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* previous one.
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*/
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for (i = 0; i < znode->child_cnt - 1; i++) {
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const union ubifs_key *key1, *key2;
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key1 = &znode->zbranch[i].key;
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key2 = &znode->zbranch[i + 1].key;
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cmp = keys_cmp(c, key1, key2);
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if (cmp > 0) {
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ubifs_err(c, "bad key order (keys %d and %d)", i, i + 1);
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err = 6;
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goto out_dump;
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} else if (cmp == 0 && !is_hash_key(c, key1)) {
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/* These can only be keys with colliding hash */
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ubifs_err(c, "keys %d and %d are not hashed but equivalent",
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i, i + 1);
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err = 7;
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goto out_dump;
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}
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}
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kfree(idx);
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return 0;
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out_dump:
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ubifs_err(c, "bad indexing node at LEB %d:%d, error %d", lnum, offs, err);
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ubifs_dump_node(c, idx);
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kfree(idx);
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return -EINVAL;
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}
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/**
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* ubifs_load_znode - load znode to TNC cache.
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* @c: UBIFS file-system description object
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* @zbr: znode branch
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* @parent: znode's parent
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* @iip: index in parent
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*
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* This function loads znode pointed to by @zbr into the TNC cache and
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* returns pointer to it in case of success and a negative error code in case
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* of failure.
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*/
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struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
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struct ubifs_zbranch *zbr,
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struct ubifs_znode *parent, int iip)
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{
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int err;
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struct ubifs_znode *znode;
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ubifs_assert(c, !zbr->znode);
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/*
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* A slab cache is not presently used for znodes because the znode size
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* depends on the fanout which is stored in the superblock.
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*/
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znode = kzalloc(c->max_znode_sz, GFP_NOFS);
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if (!znode)
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return ERR_PTR(-ENOMEM);
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err = read_znode(c, zbr->lnum, zbr->offs, zbr->len, znode);
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if (err)
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goto out;
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atomic_long_inc(&c->clean_zn_cnt);
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/*
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* Increment the global clean znode counter as well. It is OK that
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* global and per-FS clean znode counters may be inconsistent for some
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* short time (because we might be preempted at this point), the global
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* one is only used in shrinker.
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*/
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atomic_long_inc(&ubifs_clean_zn_cnt);
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zbr->znode = znode;
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znode->parent = parent;
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znode->time = ktime_get_seconds();
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znode->iip = iip;
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return znode;
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out:
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kfree(znode);
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return ERR_PTR(err);
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}
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/**
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* ubifs_tnc_read_node - read a leaf node from the flash media.
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* @c: UBIFS file-system description object
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* @zbr: key and position of the node
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* @node: node is returned here
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*
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* This function reads a node defined by @zbr from the flash media. Returns
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* zero in case of success or a negative negative error code in case of
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* failure.
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*/
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int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
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void *node)
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{
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union ubifs_key key1, *key = &zbr->key;
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int err, type = key_type(c, key);
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struct ubifs_wbuf *wbuf;
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/*
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* 'zbr' has to point to on-flash node. The node may sit in a bud and
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* may even be in a write buffer, so we have to take care about this.
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*/
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wbuf = ubifs_get_wbuf(c, zbr->lnum);
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if (wbuf)
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err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len,
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zbr->lnum, zbr->offs);
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else
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err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum,
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zbr->offs);
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if (err) {
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dbg_tnck(key, "key ");
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return err;
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}
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/* Make sure the key of the read node is correct */
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key_read(c, node + UBIFS_KEY_OFFSET, &key1);
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if (!keys_eq(c, key, &key1)) {
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ubifs_err(c, "bad key in node at LEB %d:%d",
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zbr->lnum, zbr->offs);
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dbg_tnck(key, "looked for key ");
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dbg_tnck(&key1, "but found node's key ");
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ubifs_dump_node(c, node);
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return -EINVAL;
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}
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return 0;
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}
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